Portion of a toothbrush



FIG. 1 is a perspective view as seen from the top, front and side of a portion of a toothbrush showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof, the opposite side elevation being a mirror image thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a portion of a toothbrush, as shown and described. 